Method and means for drying lumber



`Fune 9, 1925. 1,541,349

o. P. M. Goss ET A| vMETHOD AND MEANS FOR DRYING LUMBER -Fled Sept. 6,1923 Patented .lune 9, 1925.

UNITED STATES 1,541,349 PATENT OFFICE.

OLIVER 1?. M. GOSS, 0F SEATTLE, WASHINGTON, AND RALPH BI. RAWSON, 0FPORT- LAND, OREGON.

METHOD' AND MEANS FOR DRYING LUMBER.

Application filed September To all whom t may concern:

Be it known that we, OLTVER P. M. Goss, a citizen of the United States,and a resident of the city of Seattle, county of King, and State ofWashington, and RALPH H. RAW- soN, a citizen -of the United States, anda resident of the city of Portland, county of Multnomah, and State ofOregon, have invented a certain new and useful Improvement'in Methodsand Means for Drying Lumber, of which the following is a specification.

Our invention relates particularly to the kiln drying of lumber whenconsisting of a number of units, or boards, piled edgewise into a stack,with vertical spaces extending through the stack. l

In the present method of kiln drying lumber many of the pieces arefrequently so badly checked as to have to be cast aside, and thus imposea heavy loss, such checking is the result of the heated air in thechamber becoming too dry.

The object of our present invention is to 'provide a method and meansfor thoroughly drying lumber stacked as mentioned, in the shortestpractical period of time, by artificial heat maintained at just theproper degree of humidity and circulated between the units of the stack.

We attain our object by a process which may be described as consistingin so supportingand stacking the material as to provide a space at thetop, the bottom and the sides of the stack and provide vertical spacesthrough the latter. 'Ihen heating the interior of the chamber by anagency located at and arranged parallel with its sides, simultaneouslyinjecting sprays of moist hot fluid upwardly' along the sides of thechamber from a horizontal line lying midway between its top and bottom.The heating and spraying bring about the desired circulation and in thatway accomplish the thorough drying of the lumber while protecting itagainst checking due to lack of suicient moisture. We carry ourinvention into practice by the means 'diagrammatically illustrated inthe accompanying drawings, the figures of which represent as follows:

Fig. 1 is a crosssection of a kiln chamber illustrating the practicaland convenient arrangement of the coils of heating pipes and of thespray pipe which carry oury method into practice; and

l, has va e, 1923. serial N'o. 661,217.

Fig. 2 is a diagrammatic perspective of the drying chamber, showing thearrangements of the heat coils and spray pipesand a convenientconnection of the coils and pipes to a source of heated moist fluidunder pressure and a controlA for thev respective coils u and pipe.

of heating pipe d, the latter being arranged so as to lie within theperimeter of the area at the bottom of the stack only and so as not toproject beyond the bottom of the stack to the sides o-f the chamber,since the spaces g, h, z' and y" must have unobstructed communicationwith each other in order to permit the free circulation of the heatedhumidized fluid.

yAlong the sides of the coils c and c in spaces g and h midway betweenthe top and the bottom of the chamber are provided two horizontal spraypipes c and f and e and' located one above the other, each of said spraypipes being provided with spray lVents, those ofthe upper pipes e and ebeing adapted to discharge upwardly and those of the lowerpipes f and fbeing adapted to discharge downwardly.

The heating coils c and c and a?) and the spray pipes c and ,f and e andf are respectively connected to a source of heated moist fluid underpressure, preferably steam, which is usually obtainable linall'lumberyards, and the vpassage of said fluid into said coils andpipes is controlled by suitable devices as diagrammatically illustratedin Fig. 2, for example:

The steam from source s passes through a controllervalve Z, as forexample, those made by Hohman-Nelson Co. or C. J. Tagliabue and branchesto two pipes, m nand fn., lmI connects to headers m and m2 feeding sidecoils c and c and n connects with bottom header n', feeding bottom'coilsd. Each of the lines has a valve as shown which may be hand operated ormay be of the nature of a pressure regulator. The controller valve,connection from a diaphragm top to a controlling mechanism r whichinturn is connected with a thermostatic element as aov llU

't which causes the operating mechanism to open or close the valve, Z,as may be required. Such diaphragm valve and operating mechanism beingwell known. needs no further description. that the controller valve Z,will operate on either line m or n. i

rIhe line o branches oli before the steam passes through the controllingvalves Z and o in .turn is divided again into two lines o and g. gconnects with the upper set of spray lines@ and e while p connects withthe lower set of spray lines f and f. in each of these lines, 0, p and gare shown valves which may be hand operated, the one in line 0 may alsobe in the nature of a pressure regulator. Y

The operation of the kiln is brieiy as follows: Y

At the beginning of the drying period, after the kiln has been filledwith truck loads of lumber stacked on the trucks as mentioned, the steamis turned into the heating coils c and c and into theV upper spray pipese and e. The steam issuing from vents in the latter spray pipes lnducesan upward circulation in the spaces g and L, constituting fines,betweenV the sides of the stack and the sides of the chamber and theheating coils c and c promoting and i11- ducing the rise of the heatedair from these coils as indicated by the arrows u and u. The risingheated air will flow over the top of the Ylumberstack and descenddownward in the verticalspaces Je of the stack by the action of theVVgravity. F or the heated air upon coming in contact with the coolerlumber will gather moisture from the latter and become heavier and thustend to fall. After the drying process has been carried on to a certainstage, in the manner described, and the lumber having .become prettywell heated through, the upper part of the stack of lumber will benearly dry, and then circulation is reversed. Such reverse circulationis accomplished as follows: rlhe upper spray pipes e and e are shut ofiand the lower spray pipes, f and f turned on and simultaneously theheating coils c and c are turned off and the lower heating coils d areturned on, thus inducing a downward circulation of the air in the spacesg and It, the descending currents of air passing over the heating coilsi and becoming reheated move upward through the vertical spaces if: ofthe stack; the circulation being assisted by the pressure of the spraysof the fluid ejected by the lower spray pipes f andv f are indicatedbythe arrows lv and 'v'. This method of treatment clearly hastens thedrying operation of the stack of lumber in its entirety since each stepof the drying, circulation created by the steam sprays and the heatingof the air works in conformity it should l.be noted iterate with thephysicalor natural laws and in no instance opposes the/latter.

l/Ve claim:

l. The method of kiln drying consisting and injecting other sprays Vofmoist heated' Y.

fiuid in the opposite vertical directionalong the vertical sides of thechamber from a line lying between the top and the bottom of said stack,heating the interior of the chamber by an agency located at itssidessimultaneously with 'the injection of said sprays in an upwardlydirection, and heating the bottomiof the chamber under the bottom ofsaid stack simultaneously with the injection of said sprays in adownwardly direction.

2. The method of kiln drying consisting in so supporting and'stackingthe material in a chamber as to providea space at the top, the bottom,and the sides of the stack, and vertical spaces between the units ofmaterial composing the stack, heating'the interior of the chamber by anagency located at its sides, simultaneously injecting sprays of moistlheated fluid upwardly along the vertical sides of the chamber from ahorizontal line lying between its top and bottom, then discontinuingsaid heating and sprays, and heating the bottom of the chamber directlyunder the bottom of the stack only, and simultaneously injecting spraysof moist heated fluid downwardly along the vertical sides of the chamberfrom a horizontal line lying between its top and bottom.

3. ln a kiln of the character described, means forsupporting a stack ofmaterial spaced from the Hoor of the kiln chamber, a source of moistheated fiuid under pressure, heating means arranged vertically along thesides of the chamber, other heating means located at the bottom of saidchamber and entirely within an area corresponding to that of the bottomof the stack, scas not toI extend beyond the latter to the sides of thechamber, two horizontal spray pipes located one above the other at thesides of the chamber and between the top and the bottom of the stack,each of said spray pipes being connected to said source of fluid andbeing provided with vents, the vents of the upper pipe being adapted todischarge upward and those of the lower pipe being adapted to dischargedownward.

OLIVER P. M. GOSS. RALPH H. RAWSON.

